Inoculator gun with delayed action

ABSTRACT

An improvement in gas-operated inoculator guns which ensures correct operating pressure for the gun and hence a correct penetrating pressure for the inoculant. The pressure-producing piston is held back by a spring-pressed latch which is released by a plunger operated by the pressure of the gas behind the piston. The spring pressure is adjustable so that the gas pressure at which the piston is released can thereby be varied. This in turn makes it possible to adjust the pressure at which the inoculant is introduced under the skin. The latch prevents operation of the gun when insufficient pressure is available for a satisfactory inoculation.

0 United States Patent 1 I I 1 3,561,443

[72] inventor Oscar H. Banker 2,653,602 9/1953 Smoot 128/173 261Breezewood Drive, Bay Village. Ohio 2.680,439 6/1954 Sutermeister128/l73 44140 Primary Exammer-Wamer Hv Camp 121] App] No 757,932 F vFiled Sept. 1968 Attorney Charles oytech [45] Patented Feb. 9. 1971 [54]INOCULATOR GUN WITH DELAYED ACTION ABSTRhCT: An improvement n gasoperated inoculator guns which ensures correct operating pressure forthe gun and 10 Claims, 6 Drawing Figs.

hence a correct penetrating pressure for the inoculant. The [LS-Cl 173pressure-producing piston is held back by a spring-pressed 11% latchwhich is released by a plunger operated by the pressure Field ofsealdl g128/ l 73H; of the gas behind the piston. The spring pressure isadjustable 124/1 /6. I9 so that the gas pressure at which the piston isreleased can thereby be varied. This in turn makes it possible to adjustthe [56] References Cned pressure at which the inoculant is introducedunder the skin. UNITED STATES PATENTS The latch prevents operation ofthe gun when insufficient 2,605,763 8/1952 Smoot 128/ l 73 pressure isavailable for a satisfactory inoculation.

I2 2 I7 26 +1- 39 I O 13 dd -7- l M 4 78 o l 4 l I 6 Q l LULMUINOCULATOR GUN WITII DELAYED ACTION This invention relates togas-operated inoculator guns designed to replace the hypodermic needlefor injecting an inoculant under the skin of a patient.

In my prior US. Pat. No. 3,292,622 granted Dec. 20, 1966, for "PowerOperated Inoculator, there is disclosed an inoculator gun having afluid-operated piston which is connected to the rod of a smaller pistonforming part of an inoculant pump. The latter has a small orificethrough which the inoculant is ejected. The fluid for operating thepiston is preferably CO gas which is supplied from a bottle ofappropriate size for the anticipated frequencyof use of the gun. Foroccasional use, the bottle may be of a readily available 8.5 gram sizeand can be carried in the handle of the gun. In such small sizes,however, it has been found that the number of inoculations per bottle islower than expected, and furthermore, the pressure imparted to theinoculant may not besufficient toprovide a satisfactory inoculation.

The principal object of this invention is to provide an improvedgas-operated inoculator gun wherein correct operating pressure of thegun, particularly of the inoculant, is always assured.

Another object of this invention is to provide an improved gas-operatedinoculator gun by which a greater number of inoculations for the samequantity of gas is achieved.

A further object of this invention is the prevention of the operation ofa gas-operated inoculator gun when the pressure of the gas isinsufficient to produce a satisfactory inoculation.

A still further object of this invention is the provision'of agas-operated inoculator gun wherein the pressure at which the inoculantis ejected can be varied to suit the skin of the patient.

These and other objects of this invention will become apparent from thefollowing detailed description of a preferred embodiment thereof whentaken together with the accompanying drawings in which FIG. 1 is afragmentary side elevation, partly in section, of a gas-operatedinoculator gun incorporating this invention;

FIG. 2 is an enlarged end elevation of a portion of the gun of FIG. Ilooking in the direction of the arrows 22 thereof;

FIG. 3 is a plan view, partlyin section, of a portion of the gunmechanism, looking in the direction of the arrows 3-3 of FIG. 4;

FIG. 4 is an enlarged fragmentary side elevation in section of the gunof FIG. 1 showing the mechanism of this invention as it appears beforethe gun is operated;

FIG. 5 is the same enlarged fragmentary side elevation as in FIG. 4,showing the mechanism of this invention in its operated condition; and

FIG. 6 is a still further enlarged side elevational view in section ofthe pressure-operated plunger by which the operation of the inoculatoris controlled.

The objects of this invention are achieved, in its preferred form, byproviding a latch to hold the gas-operated piston of the gun againstmovement until the pressure of the gas reaches a, predetermined value.The latch is released by a small plunger extending through the gunhousing from the cylinder for the piston and thus subject at one end tothe pressure of the gas in said cylinder. When the pressure in thecylinder reaches the predetermined value, the plunger overcomes theresistance of the latch and trips the latch to free the piston. A valvein the plunger and operated by the gas-operated piston shuts off the gasto the cylinder when the said piston is freed, so that when the gas isexhausted at the end of the working stroke of the said piston and isreturned by the spring provided for this purpose, the latterpiston-holding latch is reset and the plunger is returned by the latchto its initial position. The valve in the plunger is pushed open by theentrapped gas which is pressurized by the return movement of thegas-operated piston. The valve is then held open by the piston in endposition of the latter. The resistance of the latch to movement of theplunger is provided by a spring which is adjustableto vary the gaspressure at which the inoculation is effected.

Referring now to the drawings, FIG. I is a general assembly drawingpartly in section of a gas-operated inoculator gun which incorporatesthis invention. The gun is, in general, similar to that shown in my U.S.Pat. No. 3,292,622, and is comprised of a housing 10 having a cylinderII formed therein, in which is reciprocated apiston 12 for pressurizingthe medicament to be injected. Piston 12 is connected through a suitablerod 13 to a force pump shown only in exterior outline at 14, said forcepump extracting medicament in predetermined dosages from a vial 15secured in inverted position to pump 14 by a clamp 16. Said force pump14 forces the medicament through a nozzle 17 which has a small orificeto create a small stream 18 of the medicament ejected at high pressureinto the skin of the patient. The pressure of the medicament as itleaves the noule I7, is sufficient to pierce the skin of the patient.

Piston I2 is adapted to be moved to the left, as shown in FIG. 1, on itsworking stroke by a gas such as-CO, under a pressure of about 200 poundsper square inch and contained in a bottle 19 which may be retained in ahollow handle 20 secured to the housing 10 0f the gun. Where the gun isto be used to give an occasional inoculation, a small bottle ofapproximately 8.5 grams of CO, at 800 pounds per square inch may besufficient, and such bottle is of a small enough dimension to beretained in the handle 20. Where many people are to be inoculated at thesame time, the CO may be obtained from a large cylinder connectedthrough suitable tubing to the gun.

The gas is fed through a hollow tube indicated generally at 21, to atrigger-operated valve 22, and from said triggeroperated valve through apassageway 23 in the housing 10 to the control valve 24 of the delaymechanism and thence to cylinder 11. A trigger 25, controlled manually,operates a plunger 26 which, in turn, operates the trigger-operatedvalve 22.

In prior inoculator guns not equipped with the delayed action device ofthis invention, the operation of trigger-operated valve 22 allowed gasunder pressure to enter cylinder 11 behind piston 12, and just as soonas the pressure exerted by piston 12 overcame the pressure of the returnspring 27 for said piston, said piston moved to the left and operatedpump I4. This frequently resulted in a movement of the piston which wastoo slow to develop the requisite impact pressure in pump 14 andconsequently the inoculant 18 did not leave the nozzle 17 with asufficiently high pressure to pierce the skin of the patient. It hasbeen found that a high initial inoculant pressure is required to piercethe skin, but once it is pierced the pressure can diminish considerablywithout detracting from the effectiveness of the inoculant; that is,without creating a corresponding diminution in the quantity of inoculantinjected. It is important, therefore, that the inoculant be initiallyhighly pressurized, as by a sudden activation of the piston 12, ratherthan by a gradual movement thereof. 7

Referring now to FIG. 4, there will now be described the plunger and themechanism by which the piston is restrained until sufficient pressure isbuilt up behind it to pressurize adequately the inoculant. In FIG. 4 itwill be observed that piston 12 has secured to the rear end thereof, arod 28 on the end of which is threaded a nut 29. Between nut 29 andhousing 10 are disposed a plurality of hook-shaped gages 30 (FIG. I) thefunction of which is to intercept nut 29 after a predetermined distanceof travel thereof, so as to arrest piston 12 and its associated pump 14to regulate the quantity or dosage of the inoculant injected in apatient. As shown more clearly in FIG. 2, said gages 30, when hookedover rod 28, arrest the nut 29 and its associated rod 28 and piston 12,so that by rotating said gages 30 out of the way of said nut in apredetermined number, the dosage can be regulated.

The delay device of this invention is designed to utilize nut 29 as ameans for holding piston 12 against movement in its cylinder I1 untilsufficient pressure has been built up insaid cylinder behind piston I2adequately to pressurize the inoculant.

The delay device is comprised of an oscillatable trigger 31 pivoted on apin 32 which, as shown more clearly in FIG. 3, is held by the sides of aU-shaped bracket 33. Said bracket 33 is provided with divergingattaching flanges 34 and 35 by which, as shown in FIG. 2, it is securedto housing 10. Trigger 31 has spaced ears 36 and 37 between which nut 27may be retained. Ear 36 serves to act as an abutment to prevent movementof nut 29 and its associated rod 28 and piston 12 to the left, as viewedin FIG. 4, and ear 37, as will become apparent hereinafter, serves torotate trigger 31 back to the position shown in FIG. 4, after saidtrigger has once been released and piston 12 operated.

At the bottom of trigger 31, as shown in FIG. 4, there is formed a tooth38, similar to a ratchet tooth with which is adapted to cooperate alatch 39. Said latch 39 has a tooth 40 in engagement with tooth 38, saidlatch being pivoted at 41 on a pin which is likewise retained by thesides of the U-shaped bracket 33. A leaf spring 42 is disposed in thespace between latch 39 and the bottom 43 of the U-shaped bracket. Leafspring 42 has an end 44 which is hooked under said bottom 43 and isclamped thereto by a nut 45 threaded over a thumbscrew 46. The latteris, in turn, threaded in bottom 43 and extends therethrough into contactwith the leaf spring 42. The pressure exerted by spring 42 against latch39 can be regula ted by thumbscrew 46, and the pressure selected canthen be fixed by nut 45 which acts as a lock nut for thumbscrew 46.

Latch 39 has a vertical arm 46 which extends upwardly in proximity to aplunger 47 forming part of the control valve 24. As shown more clearlyin FIG. 6, plunger 47 is slidable in a bore 48 which communicates withpassageway 23 from the tn'ggeroperated valve 22. Said plunger has aperipheral groove 49 connected by cross bores 50 to a central recess 51in plunger 47 which communicates with cylinder 11 behind piston 12 andconstitutes the means by which gas under pressure is introduced intosaid cylinder.

Within central recess 51 is disposed a three-step valve 52 the largeststep 53 being slightly loose in the central recess to allow the gas topass around it into the recess. The central step 54 has clearancebetween itself and said bore to allow gas to pass freely therebetween,and the smallest step 55 extends out of the plunger to the left intocontact with the back of piston 12. Between steps 54 and 55 is ashoulder 56 which functions as a valve with a seat 57 formed in aninsert 58 pressed into the end of plunger 47. A pair of O-rings 59disposed around plunger 47 at the sides of peripheral groove 49 seal thegroove from the atmosphere.

The right-hand end (FIGS. 4-6) 60 of the plunger 47 extends out of thehousing into contact with the adjacent face 61 of the vertical arm 46 oflatch 39. The latter is held against rotation by spring 42 as aforesaid.

The operation of the device is as follows:

Initially, the parts of the inoculator assume the positions shown inFIGS. 1 and 4. Piston 12 is at the right hand end of its cylinder 11 andhas contacted and moved valve 52 into it recess 51, so that shoulder 56is off its seat in insert 58 and hence is in its open position. Plunger47 bears against arm 46, but spring 42 holds arm 46 and pawl 39 with thetooth 40 thereof in engagement with tooth 38 of trigger 31.

When an operation of the inoculator is desired, the physician pressestrigger 25 to open valve 22 which then admits gas under 800 p.s.i. topassageway 23. The gas under pressure passes into peripheral groove 49,cross bores 50 and recess 51 where same travels to the bottom of saidrecess behind the end of valve 52 and the remainder goes around valve 52past insert 58 and into cylinder 11 behind piston 12. When theresistance of return spring 27 is exceeded by the gas pressure incylinder 11, piston 12 will try to move to the left as viewed in FIG. 1,but it will be held back by trigger 31.

The gas in cylinder 11 simultaneously pushes against the end of plunger47 which, in turn, pushes against arm 46 to turn latch 39 and releasetrigger 31. Spring 42 resists plunger 17, in the example shown, with a3-to-1 mechanical advantage. Thus pressure continues to build up incylinder 11 instead of being dissipated in movement of the piston. untilsaid pressure reaches a predetermined value. Said value in one form wasfound to be satisfactory at.200 p.s.i. It may be apparent that the lowerthe pressure the less volume of gas used. At such pressure, spring 42gives way, latch 39 is turned clockwise, as viewed in FIG. 5, andtrigger 31 is pushed out of the way by nut 29 as piston 12 is freed toperform its work.

As soon as plunger 47 moves away from piston 12, valve 52 is pushed bythe pressure of the gas in recess 51 behind said valve upon seat 58 toclose said recess to the cylinder 11. This shuts off further flow of gasunder pressure to cylinder 11, and piston 12 is moved by the expansionof the gas held captive behind said piston. The movement of piston 12 isextremely fast and creates a tendency to spin trigger 31 around pin 32and excessive amount which would leave it in an undesired position forthe next cycle. Accordingly, movement of trigger 31 is slowed by theintroduction of a ball 62 (FIG. 3) held by a spring 63 against a hole 64inside of U-shaped bracket 33. Spring 63 is in a recess 65 in trigger 31and hence reacts upon said trigger to hold it against the opposite sideof the bracket. This creates a friction force which further retards thefree movement of trigger 31 so that after nut 29 passes over thetrigger, the latter assumes the position shown in FIG. 5. The expandedgas in cylinder 11 will remain captive therein as long as the trigger 25is held in its operative position by the physiclan.

When the physician releases trigger 25, valve 22 is so constructed thatit will exhaust passageway 23 and the cylinder 11 connected thereto.With the gas exhausted out of said cylinder, return spring 27 becomeseffective to push piston 12, its rod 28 and nut 29 back to the positionshown in FIG. 4. In the process, nut 29 engages ear 37 and turns trigger31 in a clockwise direction as shown in FIGS. 4 and 5, until tooth 40 oflatch 39 again engages tooth 38 of trigger 31 because of the continuousupward pressure exerted by spring 42 against latch 39.

Thus the device of this invention provides a means for preventingoperation of a gas-operated inoculator until a predetermined pressure iscreated in the operating cylinder of the inoculator, and if suchpressure is not available because of exhaustion of the source, theinoculator will not operate to produce an incomplete inoculation andhence will not waste the inoculant. Should the physician wish toinoculate a child with its typically tender skin, he can reduce theoperating pressure by appropriately adjusting thumbscrew 46 to reducethe pressure exerted by spring 42.

It is understood that the foregoing description is merely illustrativeof a preferred embodiment of the invention and that the scope of theinvention therefor is not to be limited thereto, but is to be determinedby the appended claims.

lclaim:

1. In combination a pressure fluid operated device comprising a housingforming a cylinder, a piston in said cylinder adapted to perform work,an abutment rigidly connected to said piston, a trigger pivoted on saidhousing and adapted to cooperate with said abutment to hold or releasesaid abutment, a source of gas under pressure for moving the piston inone direction, means forming a passageway connecting the gas source withthe cylinder on one side of said piston to move said piston in said onedirection, a valve in the passageway and controlling passage of gastherethrough, and means operated by the pressure of gas underpredetermined unit pressure in said cylinder for operating said triggerto release said trigger and said abutment on said piston.

2. The combination described in claim 1, said abutment comprising a rodsecured to said piston and extending through the housing to the exteriorthereof, and a radially disposed face on said rod cooperable with saidtrigger.

3. The combination described in claim 2, there being a return spring inthe cylinder to move the piston and rod in the opposite direction tosaid one direction, an abutment on the trigger, engageable by said rodfor reversing the movement of the trigger upon movement of said piston,and rod in the opposite direction, whereby to reset the trigger.

4. The combination described in claim I, said means operated by thepresence of gas under predetermined pressure including a shutoff valve,and means movable with the piston for operating said shutoff valvewhereby to fix the quantity of gas under pressure in the cylinder.

5. The combination described in claim 1, said means operated by thepresence of gas under predetermined pressure comprising a plunger in thehousing and exposed on one side to the pressure of the gas in thehousing, a pivoted latch bearing against the other side of said plunger,a spring bearing against said latch to hold it against said plunger,said trigger adapted to be held in one position by said latch, saidtrigger in its latch-held position providing anabutment against whichthe abutment connected to said piston may bear.

6. The combination described in claim 5, and means for adjusting thepressure of the spring against the latch, whereby to adjust the unitpressure of the gas at which the latch is operated by the plunger.

7. The combination described in claim 5, said spring comprising a leafspring, a plate secured to the housing, said spring having its endhooked around said plate, aligned openings in the hooked end and in theplate, said opening in the plate being threaded, and a thumbscrew in theopenings and bearing against the spring to adjust the pressure of thespring against the latch, said thumbscrew also holding the spring on theplate. I

8. The combination described in claim 5, said means operated by thepressure of gas under predetermined pressure including a shutoff valvedisposed in the plunger. and means movable with the work piston foroperating said shutoff valve, whereby to fix the quantity of fluid underpressure in the cylinder.

9. The combination described in claim 1, and means interposed betweensaid housing and said trigger to retard movement of said trigger.

10. The combination described in claim 1, said housing comprising aU-shaped bracket, said trigger being pivoted between the sides of theU,'- a recess in the side of the trigger adjacent one of the sides ofthe bracket, and a ball and a spring in said recess, said springpressing the ball against one side of the U" and the trigger against theother side of the U to create friction forces to retard movement of saidtrigger relative to said bracket.

1. In combination a pressure fluid operated device comprising a housingforming a cylinder, a piston in said cylinder adapted to perform work,an abutment rigidly connected to said piston, a trigger pivoted on saidhousing and adapted to cooperate with said abutment to hold or releasesaid abutment, a source of gas under pressure for moving the piston inone direction, means forming a passageway connecting the gas source withthe cylinder on one side of said piston to move said piston in said onedirection, a valve in the passageway and controlling passage of gastherethrough, and means operated by the pressure of gas underpredetermined unit pressure in said cylinder for operating said triggerto release said trigger and said abutment on said piston.
 2. Thecombination described in claim 1, said abutment comprising a rod securedto said piston and extending through the housing to the exteriorthereof, and a radially disposed face on said rod cooperable with saidtrigger.
 3. The combination described in claim 2, there being a returnspring in the cylinder to move the piston and rod in the oppositedirection to said one direction, an abutment on the trigger, engageableby said rod for reversing the movement of the trigger upon movement ofsaid piston, and rod in the opposite direction, whereby to reset thetrigger.
 4. The combination described in claim 1, said means operated bythe presence of gas under predetermined pressure including a shutoffvalve, and means movable with the piston for operating said shutoffvalve whereby to fix the quantity of gas under pressure in the cylinder.5. The combination described in claim 1, said means operated by thepresence of gas under predetermined pressure comprising a plunger in thehousing and exposed on one side to the pressure of the gas in thehousing, a pivoted latch bearing against the other side of said plunger,a spring bearing against said latch to hold it against said plunger,said trigger adapted to be held in one position by said latch, saidtrigger in its latch-held position providing an abutment against whichthe abutment connected to said piston may bear.
 6. The combinationdescribed in claim 5, and means for adjusting the pressure of the springagainst the latch, whereby to adjust the unit pressure of the gas atwhich the latch is operated by the plunger.
 7. The combination describedin claim 5, said spring comprising a leaf spring, a plate secured to thehousing, said spring having its end hooked around said plate, alignedopenings in the hooked end and in the plate, said opening in the platebeing threaded, and a thumbscrew in the openings and bearing against thespring to adjust the pressure of the spring against the latch, saidthumbscrew also holding the spring on the plate.
 8. The combinationdescribed in claim 5, said means operated by the pressure of gas underpredetermined pressure including a shutoff valve disposed in theplunger, and means movable with the work piston for operating saidshutoff valve, whereby to fix the quantity of fluid under pressure inthe cylinder.
 9. The combination described in claim 1, and meansinterposed between said housing and said trigger to retard movement ofsaid trigGer.
 10. The combination described in claim 1, said housingcomprising a U-shaped bracket, said trigger being pivoted between thesides of the ''''U,'''' a recess in the side of the trigger adjacent oneof the sides of the bracket, and a ball and a spring in said recess,said spring pressing the ball against one side of the ''''U'''' and thetrigger against the other side of the ''''U'''' to create frictionforces to retard movement of said trigger relative to said bracket.